Hey jesssuper,
Welcome to Apple Support Communities.
To start we recommend making sure both devices are up-to-date. Keeping devices up-to-date ensures you have the latest features, security updates, and fixes.
If you need steps to check for update on your iPhone and iPad, follow them below or review them in this article: Update your iPhone or iPad.
1. Back up your device using iCloud or your computer.
2. Plug your device into power and connect to the internet with Wi-Fi.
3. Go to Settings > General, then tap Software Update.
4. If you see more than one software update option available, choose the one that you want to install.
5. Tap Install Now. If you see Download and Install instead, tap it to download the update, enter your passcode, then tap Install Now. If you don't know your passcode, learn what to do.
Also, check for app updates and install them. App updates include fixes. To check for updates, click here: How to manually update apps on your Apple device.
Confirm that both devices are signed in using the same Apple ID. You can confirm by following the steps here or in this article: Access your Apple Arcade gameplay data on all of your devices .
1. Make sure that you're signed in to iCloud with the same Apple ID that you use on your other devices.
2. Make sure that you're signed in to Game Center with the same Apple ID that you use on your other devices. Go to Settings > Game Center to see the Apple ID that you're using with Game Center.
If it continues to happen, try a different Wi-Fi network if possible. We ask that you try a different network to ensure it isn't related to a particular network.
You mentioned making sure Farmside was turned on in iCloud settings. If you didn't check iCloud Drive, make sure it is on per step 3 in the screenshot. Both of them needs to be on in order for the data to sync.
If none of the information above helps, and you're only experiencing this issue with Farmside, we suggest reaching out to the app's developer support. They are the experts and should be able to further investigate this with you. If you're unsure how to access their support, this article should help: How to contact an app developer. The article has steps that will show you where to go to contact an app's developer support.
Hope this helps. Take care.